Forest management affects regional rates of carbon sequestration.  However, other biophysical and human factors might impact rates of carbon sequestration by forests as well.  In the Central Appalachian Mountains, nitrogen deposition might impact productivity and sequestration, though the direction of the effect may vary with rates of deposition.  In this paper, we present results showing the impacts of timber harvest strategy on carbon sequestration and then describe a new study focused on the impacts of nitrogen-deposition on carbon sequestration by high elevation forests in West Virginia.  Though West Virginia’s forests have been aggrading since the early 1900s, a variety of forest management approaches have been applied in this region including clearcutting and selective harvest.  Combining tree-rings records with ecosystem models, we compared net primary productivity, net ecosystem productivity and carbon flux among ecosystem compartments in response to four harvest histories (no harvest, clear-cutting, single tree selection cutting and 43 cm diameter-limit cutting) in order to evaluate the impact of timber management on carbon sequestration in the Central Appalachian region.

Results/Conclusions

We developed a modified version of PnET updated to include nitrogen cycling for a forest in stage 2 of nitrogen saturation.  This modified version outperformed the original model, suggesting that nitrogen deposition is affecting productivity and carbon cycling in this region.  Based on this revised version of PnET, we found that clearcutting had short-term negative effects on net ecosystem productivity. Average plant carbon since 1950 was about 33% lower in response to a clear-cut event than in an un-harvested forest.  Carbon sequestration associated with clearcutting practices declined over time and resulted in lower carbon storage then diameter-limit cut, selective cut, or un-harvested forests.  Our new study will explore the impact of nitrogen deposition on forest productivity in high elevation forests in West Virginia using tree ring estimates of tree productivity combined with remotely sensed estimates of leaf nitrogen and nitrogen-deposition.